One bug that has appeared on both webOS phones and the TouchPad is when calendar entries lose any connection with a synergy account, and therefore get assigned to an "undefined" account. As a result of being divorced from a calendar account, you can't just remove the account to delete these items; instead, you would need to manually delete each calendar entry one at a time which is usually not a viable option. Luckily, Homebrew developer MetaView has been able to build some functionality into his homebrew app AgendaZ to delete these orphaned calendar entries for you. As long as you are on webOS 2.0 or higher and running version 0.6.3 or higher of AgendaZ, you can swipe down from the top-left to access the Application dropdown menu, select Preferences, and then toggle "Delete Orphaned" to YES in the "AUTO-CLEANUP EVENTS" section. Then, whenever you load up a listing of your calendar events, AgendaZ will delete any events in that timeframe that do not belong to one of your synergy calendar accounts.

If you combine this with the Auto Launch preference of AgendaZ to launch the app every day, you can always be assured that at least the most recently days (or weeks) on your calendar will always be clear of undefined accounts. You will also see a "Delete Doubles" option that will simply delete any duplicate calendar events that show up across all of your accounts. Unfortunately, there is no way to specify ahead of time which account the event should be deleted from, so be careful using this option.

AgendaZ is available for all devices running webOS 2.0 or higher in the webOS Nation Homebrew Gallery and can be installed using Preware, webOS Quick Install or any other homebrew solutions